This invention relates to apparatus and methods for enabling the use of cellular phones for communication while at sea (offshore) using a cellular infrastructure.
A problem exists in that there is currently no cost effective mobile communication system available for individuals when more than a few miles out at-sea, other than on-board ship radio systems. A need exists for an economical and reliable communication system which allows users of cell phones to use their mobile units when more than a few miles out at sea such that they can communicate with other users out at sea and also reach an on-shore network. Currently, as shown in FIGS. 1 and 2, the typical range for cellular service at sea is approximately 2 miles off the coastline of the mainland (e.g., the United States). This is possible due to an existing cellular network which consists of cellular towers that transmit/receive located along the shore line, as shown in FIGS. 1 and 2. These figures illustrate the deployment of transmit/receive cell towers in a land based cellular system. As shown, a geographic area may be divided into contiguous hexagonal areas (each hexagon defining a “cell”) with transmit/receive cell towers located in the center of the hexagon (cell). In FIGS. 1 and 2, by way of example, the distance from the center antenna tower to the coverage edge is shown to be approximately 1.7 miles. Therefore, as shown in FIG. 2, a mobile user can access cellular towers located along the coastline for a distance of up to approximately 1.7 miles off the coast. A cell phone can not be used reliably much beyond this limited distance.
This presents a very limited range and a significant problem. By way of example, fishermen or any one on any ship going 5-20 miles out to sea can not use their mobile cell phones to communicate with others out at sea or with any one on shore.
An object of the invention is to provide a cellular communication system which enables cellular communication over a large expanse of water and between points at a significant distance from shore to other points on-shore and off-shore.